Java tutorial
/** * Copyright (c) 2011, Thilo Planz. All rights reserved. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License as * published by the Free Software Foundation, either version 3 of the * License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package v7cr; import java.util.List; import javax.servlet.ServletContext; import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener; import org.apache.commons.io.IOUtils; import com.mongodb.DB; import com.mongodb.DBCollection; import com.mongodb.DBObject; import com.mongodb.Mongo; import com.mongodb.util.JSON; /** * Manages the connection to MongoDB */ public class InitDB implements ServletContextListener { public void contextDestroyed(ServletContextEvent e) { } @SuppressWarnings("unchecked") public void contextInitialized(ServletContextEvent e) { try { Mongo db = new Mongo(); ServletContext c = e.getServletContext(); c.setAttribute(getClass().getName(), db); // check if the "roles" collection // exists, if not create it if (getDBCollection(c, "roles").findOne() == null) { String json = IOUtils.toString(getClass().getResourceAsStream("roles.json"), "UTF-8"); List<DBObject> l = (List<DBObject>) JSON.parse(json); DBCollection roles = getDBCollection(c, "roles"); for (DBObject r : l) { r.put("_version", 1); roles.save(r); } } } catch (Exception ex) { throw new RuntimeException(ex); } } static Mongo getMongo(ServletContext c) { return (Mongo) c.getAttribute(InitDB.class.getName()); } static DB getDB(ServletContext c) { return getMongo(c).getDB("v7cr"); } static DBCollection getDBCollection(ServletContext c, String name) { return getDB(c).getCollection(name); } }